Lead and Zinc Pigmented Mural Paint: Discovering Ancient Technologies at Lowry Pueblo Great House in Southwest Colorado

At Lowry Pueblo, small fragments of painted plaster are all that remain of a bold white step pattern mural that once decorated Kivas A and B. We used the following analytical techniques to study these fragments: visual microscopic analysis, portable X-ray fluorescence, scanning electron microscopy with an energy dispersive X-ray spectrometer, powder X-ray diffraction, and radiocarbon dating. We identified zinc oxide and lead sulfate pigment minerals in the glossy white paint, whereas calcium carbonate was identified as the pigment for the matte white paint. Radiocarbon dating of a lead layer places mural production at 1030–1210 cal A.D., consistent with occupation at Lowry Pueblo Great House. Stratigraphic analyses of the painted plaster layers reveals that underlying glossy white paint was applied before the ultimate matte white layer. The change in pigment source and paint recipes demonstrate a design-modifying choice made by the kiva painters.